Riser construction for casting apparatus

ABSTRACT

A riser assembly for use with a mold having a pair of separable parts includes a pair of sections that are resiliently and pivotally mounted on the respective mold parts. As the mold parts are moved together to define a casting cavity, the riser parts simultaneously define a riser cavity and are urged into sealing engagement with the mold parts.

United States Patent Inventor Richard O. Peck Elk Grove Village, Ill.

Appl. No. 865,459

Filed Oct. 10, 1969 Patented Oct. 19, 1971 Assignee AMSTED Industries Incorporated Chicago, Ill.

RISER CONSTRUCTION FOR CASTING APPARATUS Primary Examiner-H. A. Kilby, Jr. Attorneys-Walter L. Schlegel, Jr. and Russell W. Pyle ABSTRACT: A riser assembly for use with a mold having a 3claims4nnwing Figs pair of separable parts includes a pair of sections that are 11.8. CI 249/105 resiliently and pivotally mounted on the respective mold parts. Int. Cl B29c 9/08 As the mold parts are moved together to define a casting cavi- Field of Search 249/105, ty, the riser parts simultaneously define a riser cavity and are 108; 18/ 12 DH, 42 RR urged into sealing engagement with the mold parts.

38 I l 82 g? 3g t 86 e M 70 66 fi; I w 59 59 ,4- s 90 f l 1' 60 'l", y 51 i" 50 78 e 35 e a 54 PATENTEDnm 19 IHTI 3,614,053

SHEET 10F 2 PATENTEUDCT 19 1911 3, 14,053

SHEET 2 OF 2 RISER CONSTRUCTION FOR CASTING APPARATUS This invention relates to a casting apparatus and more particularly to an improved riser construction and mounting for a permanent mold having separable parts.

- The riser construction herein described is particularly adaptable to a permanent mold apparatus having separable or movable parts that at least partially define the casting cavity thereof, such as that described in US. Pat. No. 3,340,926 to Sylvester, incorporated herein by reference. The mold apparatus therein described comprises a pair of movable side blocks and a plurality of inner blocks, including top, bottom and end blocks. The inner blocks are clamped between the side blocks by a screw or hydraulic power device acting in compression on the side blocks in such a manner as to define a casting cavity. An ingate is provided in the bottom of the mold through which molten metal is forced upward into the casting cavity, and a riser at the top of the mold in communication with the casting cavity holds additional molten metal to feed any shrinkage in the casting that may occur during solidification. The riser is normally a separate part and must be sealed to the mold to prevent leakage between the riser and the mold during the casting operation. After the casting cavity of the mold has been filled and the metal therein has solidified, the side blocks are separated to enable removal of the casting, and the mold is prepared for a subsequent casting operation. In so doing, the riser assembly must also be moved to a position where it will not interfere with removal of the casting and should preferably be adaptable to the reuse of the mold apparatus.

The riser described in the aforementioned patent is essentially a one-piece construction formed of a refractory materi al. The use of such a construction, however, has been found to be inconvenient because the riser must be freshly mounted on and sealed to the mold assembly with each successive casting operation. Additional problems may arise when the side blocks of the mold are separated.

An object of this invention is to provide a permanent riser construction for use with a permanent mold having separable parts, which construction will not interfere with the separation and assembly of such parts.

Another object of this invention is the provision in connection with a mold having separable parts of a riser assembly that will accommodate thermal distortions in and between the mold parts as such may occur during the casting operation.

Other objects will become apparent from the following description and appended claims, taken in connection with the accompanying drawings, wherein:

FIG. 1 is a vertical sectional view of a permanent slab mold to which the teachings of the presently described invention are applicable;

FIG. 2 is a fragmentary plan view of one end of the mold shown in FIG. 1 illustrating details of the novel riser assembly;

FIG. 3 is a fragmentary sectional view taken along section line 33 ofFIG. 2; and

FIG. 4 is a simplified schematic view of a portion of the riser assembly, showing a diagram of the forces generated within the assembly.

With more particular reference to the drawings, FIG. 1 shows one type of mold to which the novel riser construction is applicable, although it will be understood that such construction may be applied to other molds having movable parts. The mold shown comprises a pair of spaced side graphite blocks and 11 (See FIGS. 2 and 3) and a plurality of inner blocks including a bottom block 12 supported by a foundation l4, spaced rear 16 and forward 18 vertical end blocks resting on said bottom block and supported by respective supports 20 and 22, and a top block 24 resting upon the rear end block and supported above by a support 26. Suitable mechanical or power devices 28 acting on the side blocks 10 and II. are provided adjacent each end of the mold, in order to move the side blocks toward and away from the inner blocks. Immediately prior to the casting operation, the side blocks are compressed or clamped against the inner blocks to define a casting cavity 30.

The mold shown is designed to be filled at the bottom from a pressurized source of molten metal (not shown) through an ingate 32 located between the bottom block 12 and the forward end block 18 and leading to the casting cavity 30. The riser, generally indicated at 34, is located at the top of the mold in a position above a gate 35 between an extension 42 of the forward end block 18 and the adjacent end of the top block 24. The riser forms a reservoir or cavity 25 above the level of the mold for retaining a relatively small amount of molten metal.

FIGS. 2 and 3, taken in connection with FIG. I, show the riser and its mounting in detail. The body of the riser 34 comprises a pair of opposed curved sections 36 and 38 substantially semicylindrical in shape, the lower flat surfaces of which rest on corresponding upper flat surfaces of which rest on corresponding upper flat surfaces of the respective side blocks 10 and 11. A spacer 40 (FIG. 3) may be interposed between each riser section and its corresponding side block in order to provide protection against chipping or galling of the side blocks.

When assembled, the riser sections 36 and 38 present opposing pairs of vertical planar surfaces, 37 and 39, and 41 and 43, respectively, which abut opposite sides of the extension 42 on the forward end block 18 and a backing block 44 secured to and extending vertically from the end of the top block 24 and spaced from said extension (FIGS. 1 and 2). The riser sections 36 and 38, together with the top block extension 42 and backing block 44 thus define the reservoir or cavity 25 in communication with the gate 35 in the top of the mold.

The riser sections 36 and 38 are not connected to one another, but are independently mounted upon respective flasks 54 and 55 that retain and support the respective side blocks 10 and 11, and thus the riser sections move with the movement of the side blocks. Special mountings, generally indicated at 50 and 52, connect the respective riser sections to the respective flasks, and inasmuch as both mountings are substantially identical, only one will be described in detail for the sake of brevity.

As best shown in FIGS. 2 and 3, each mounting 50 and 52 includes means to enable pivotal movement of the respective riser sections 36 and 38 relative to the respective side blocks 10 and 11. Each mounting comprises a pivot base 51 having a bottom wall 53 secured to the flask 54 and a pair of spaced vertical sidewalls 56 and 58 extending upward from said bottom wall. A transverse member 60 secured between the sidewalls 56 and 58 has an aperture 62 therein for rotatably receiving and supporting one unthreaded end of an adjustment screw 64, said end having an extension 59 adapted for engagement by a wrench. The other end of the screw is rotatably supported in an aperture 66 of a second bracket 68 secured to the flask. A trunnion nut 70 is in threaded engagement with the central threaded portion of the adjustment screw 64 and includes a pair of coaxial pins 72 and 74 extending therefrom in opposite directions along an axis substantially perpendicular to the axis of the screw.

Means are provided for rotatably mounting the riser section 36 around the pins 72 and 74 of the trunnion nut 70. Spaced upper and lower beams 76 and 78 (FIG. 3) are secured to the riser section 36 and are resiliently connected to one end of a pivot member 80 by means of pairs of spring groups, such as 82, between each beam and the pivot member and bolts 84 passing through each spring group and interconnecting said beams and pivot member. The other end of the pivot member 80 includes a pair of spaced trunnion blocks 86 and 88 having apertures for rotatably receiving the pins 72 and 74 of the trunnion block. A pair of spaced arms 90 and 92 are secured to and extend from the pivot member 80 and contact the upper surface of the lower spring beam 78.

The mounting as described above causes the riser sections 36 and 38 to be forced downward into sealing engagement with the respective top blocks 10 and 11 when the side blocks are moved toward one another in preparation for the casting operation. The screw 64 is first adjusted such that the riser section 36 slightly overhangs the edge of the side block 10.

Also, the bolts 84 between the pivot member 80 and the beams 76 and 78 are tightened to precompress the spring groups 82. When the side blocks are closed, the riser sections 36 and 38 engage and seal against the front block extension 42 and backing block with a compressive force that is preferably sufficient to compress the spring groups 82 beyond their point of precompression, thereby providing a resilient connection to accommodate thermal distortions in the mold and riser and insuring that the proper and required loads are generated within the mounting system.

From FIGS. 2-4, it may be understood that when the side blocks and l l are brought together in compression, a reaction force is exerted in the opposite direction. The mounting is designed such that the line of reaction force P (FIG. 4) exerted on the riser section 36 is located between the axis of rotation A of the pivot member 80 and a point of contact of the riser section with the mold, thereby resulting in a torque on the pivot member. The arms 90 and 92 on the pivot member 80 transmit the torque generated in the fonn of a downward force F (FIG. 4) on the lower beam 78 and hence on the riser section 36, thereby effecting a seal between the riser section and the top block 10 or spacer 40.

it should be noted that the spring groups are selected to have the necessary capacity for supporting the riser when substantially full of molten metal, and therefore the lower spring groups may have a higher capacity than the upper groups to counteract the increased forces nearer the bottom of the riser exerted by the weight of the metal. Also, the adjustment screw 64 allows proper horizontal positioning of the riser section 36 relative to the casting surface of the side block 10 after such surface has been reconditioned by machining.

It may be seen that the mounting described above may be used in connection with molten metal transfer subassemblies other than the particular riser described herein. The present invention also contemplates the use of an independent force to compress the riser sections to result in the exertion of pressure of such sections on mold parts.

Having thus described the invention, what is claimed is:

1. In a mold wherein the casting cavity thereof is defined by a pair of movable side blocks supported by flasks and a plurality of inner blocks including horizontal top and bottom blocks and vertical front and rear end blocks, and a riser is provided at the top of the mold and includes a pair of opposed sections mounted on respective side blocks and abuttable with a block extending vertically from the top block and a vertical extension of the front end block to define a reservoir in communication with the casting cavity, the improvement in said riser comprising a pair of opposed supports secured to respective flasks and extending above said side blocks, a pair of opposed frames pivotally mounted on respective supports, and means for connecting said frames to respective riser sections such that the connection is resilient with respect to horizontal forces between said frames and riser sections and rigid with respect to downward forces from said frames to said sections, said last-mentioned means comprising upper and lower spring groups between each frame and its respective section, means for prestressing said springs, and a pair of spaced arms extending from each frame and contacting its respective riser section in such a manner as to transmit downward forces from said frame to said section.

2. A riser construction for use with a mold having a casting cavity, the riser including a plurality of parts contacting the mold and defining a passage in communication with the casting cavity, characterized by means pivotally mounting at least two of said parts, the last-mentioned parts contacting the mold between their respective pivotal axes and said passage, and separate resilient means for exerting forces on said last-mentioned parts to cause all of said parts to move into contact, said forces acting along lines between said pivotal axes and the point of contact of the last-mentioned parts with the mold such that the parts are resiliently urged against the mold, wherein the pivotal mounting means includes a pair of opposed supports, a pair of opposed frames pivotally mounted by pins to respective supports, the separate resilient means mcluding upper and lower springs group between each frame and its respective riser part, and a pair of spaced arms extending from each frame and contacting its respective riser part in such a manner as to transmit downward forces from said frame to said part.

3. A riser construction according to claim 2, wherein adjusting means are provided for moving said two riser parts toward and away from each other, said adjusting means comprising a screw rotatably supported at both ends and having a nut mounted on pins which are pivotally received in respective frames. 

1. In a mold wherein the casting cavity thereof is defined by a pair of movable side blocks supported by flasks and a plurality of inner blocks including horizontal top and bottom blocks and vertical front and rear end blocks, and a riser is provided at the top of the mold and includes a pair of opposed sections mounted on respective side blocks and abuttable with a block extending vertically from the top block and a vertical extension of the front end block to define a reservoir in communication with the casting cavity, the improvement in said riser comprising a pair of opposed supports secured to respective flasks and extending above said side blocks, a pair of opposed frames pivotally mounted on respective supports, and means for connecting said frames to respective riser sections such that the connection is resilient with respect to horizontal forces between said frames and riser sections and rigid with respect to downward forces from said frames to said sections, said last-mentioned means comprising upper and lower spring groups between each frame and its respective section, means for prestressing said springs, and a pair of spaced arms extending from each frame and contacting its respective riser section in such a manner as to transmit downward forces from said frame to said section.
 2. A riser construction for use with a mold having a casting cavity, the riser including a plurality of parts contacting the mold and defining a passage in communication with the casting cavity, characterized by means pivotally mounting at least two of said parts, the last-mentioned parts contacting the mold between their respective pivotal axes and said passage, and separate resilient means for exerting forces on said last-mentioned parts to cause all of said parts to move into contact, said forces acting along lines between said pivotal axes and the point of contact of the last-mentioned parts with the mold such that the parts are resiliently urged against the mold, wherein the pivotal mounting means includes a pair of opposed supports, a pair of opposed frames pivotally mounted by pins to respective supports, the separate resilient means including upper and lower springs group between each frame and its respective riser part, and a pair of spaced arms extending from each frame and contacting its respective riser part in such a manner as to transmit downward forces from said frame to said part.
 3. A riser construction according to claim 2, wherein adjusting means are provided for moving said two riser parts toward and away from each other, said adjusting means comprising a screw rotatably supported at both ends and having a nut mounted on pins which are pivotally received in respective frames. 